Loss of compressed air, brakes could fail

[MrTransistor]

Hi All,

This is just an FYI to be filed away for the future. The other day we started to leave Dauphin Island, Al. and after several minutes, I noticed that the air pressure was still to low to silence the alarm. Investigating, I found that the high-pressure hose from the engine driven air pump to the Haldex de-humidifier had developed a fairly large leak. It could build up no more than 45 PSI and if it had failed while traveling, the air brakes would have activated and left us stranded on the road.

I called Freightliner and was told that that was a non-stocked part and that the lead-time was 56 days to have one made by the manufacturer (Freightliner part number A1215912084) and shipped out. This is a stainless steal braid covered Teflon hose with compression fittings on both ends that takes a 1 ¼” wrench to loosen.

At that point, I thought of having one made by a hydraulics and high-pressure air hose company and after a few phone calls, I located Bayside Rubber and Products Inc. in Mobile that will make hoses on the spot. We drove to their location with the old hose (it’s about 8 feet long and no more than 1” in diameter) and a guy named Miles made a brand new one in less than 10 minutes.

The old hose failed because it was installed along the frame rail and made a rather bad bend where it came to a Winnebago installed bulkhead with a very sharp screw that was rubbing on the hose. After 85,000 miles, it finally wore a hole in the hose. The other bad thing about the way the hose was installed was that after it left the frame rail on its way to the Haldex, there was a hose clamp that anchored it to the transmission housing. This placed a bad strain as well as additional unnecessary vibration on the hose. Leaving the clamp off allowed the hose to take a natural curve to the Haldex that kept it around 8” away from the transmission. Go figure!

If you ever have occasion to have the engine access cover off, this may be something to inspect. Look for unusual bends and objects that the hose may be in contact with that could rub. Even though it was made of Teflon, it couldn’t handle the point of a screw forever.

The thing to file in memory is that these hydraulic and high-pressure air outfits can usually make any hose you may need on a diesel engine. If not they should be able to point you to an outfit in the area that can. In Mobile the place to go is:

(251)660-0902
Bayside Rubber and Products Inc.
4083 Halls Mill Rd.
Mobile, Al. 36691

[Wayne M]

Good informaiton.
Thanks.